"It's unfortunate that the Internet has destroyed the business model of the record labels," he said. "But that is not the fault of radio, which continues to build and nurture the careers of countless artists through free radio airplay."

Free radio airtime "remains an unparalleled promotional platform for music, generating untold billions in album and concert sales and merchandising opportunities," he said. Therefore, radio stations should not have to pay royalties to singers.

"The music community has been fighting since the early days of radio to close the copyright loophole," she wrote. "Other radio platforms -- satellite radio, Internet radio and cable TV music channels -- pay performance royalties. Even AM and FM music radio stations that stream their signal online -- same music, same DJs, same ads -- pay performance royalties. They do not pay for over-the-air broadcasts."

Both sides have ratcheted up their lobbying over the past month, although it's unclear how soon the Performance Rights Act, which has passed judiciary committees in both chambers, will hit the floor.